The place I live is pretty much wall-to-wall Asians, and the cracks left over are filled in with Hispanics (most blacks seem to live in the East bay)*. All the Asian women I know could chew a hole in a brick wall and still have enough piss and vinegar left to kick your ass when she got to the other side. Despite being about three feet tall and about 80 pounds soaking wet.

From personal experience, I don't know where the "demure Asian woman" stereotype ever got started.

*There have been a couple times at the big mall where I've looked around and I'm the only "white" person in eyeshot. Weird. This may happen more often than I've noticed, but I normally don't pay much attention.